Transformer



June 8 1926. 1,588,171

. R. H, CHADWICK TRANSFORMER Filed Sept 11, 1925 F'Lgl.

Tnve ntor": Ralph HCnaqv/Lck,

9 Ls Attorney.

Patented June 8, 1926 UNITED STATES PATENT OFFICE.

RALPH H. CHADWICK, OF FORT WAYNE, INDIANA, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

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Applloatlon filed September limit the current supplied by the secondarywinding of the transformer to a safe value. The reactance of a transformer increases with the leakage magnetic flux and the gen eral object of the invention is to provide an improved construction and arran ement of transformer core and windings whereby the leakage flux and the reactance may be of large value. High reactance transformers are useful for operating bells, electric toys, high voltage testing apparatus,'spark plugs for igniting the oil vapor in oil heaters and for various other purposes.

The invention will be better understood from the following description taken in connection with the accompanying drawings in which Fig. 1 is a perspective view of a transformer constructed in accordance with the invention, and Figs. 2 and 3 are views showing the construction of the laminations of the core.

The transformer shown in Fig. 1 comprises a primary winding 10, a secondary winding 11 and a laminated magnetic core 12. Each lamination of the core 12 comprises an outer element or section 13 and an inner element or section 11. The outer sections 13 are secured together in a hollow rectangular stack to form the yokes 15 and two outer legs 16 of the core. The inner sections 11 are secured together to form the -winding leg 17 of the core with integral side extensions 18 nearly reaching the two outer legs 16. The two ends of the winding leg 17 fit tightly into notches in the inner edges or faces of the yokes 15. The length of the winding leg 17 is such that when forced into position between the notches in the yokes 15 it will be retained by friction. An accurate and tight fit between the sections 13 and 14 of the laminations may he assured by punching the inner sections .11 from the same positions in the outer sections 13 that they are to occupy when assembled. A small projection 19 on one end of the Winding leg 17 may be provided to prevent reversal of the inner sections 14 in position as they are being assembled.

The primary and secondary windings 10 11, 1925. Serial No. 55,831.

and 11 surround opposite ends of the winding leg 17 and are separated by its side extensions 18. Thin non-magnetic air gaps 20 are left between the outer ends of the side extensions 18 and the adjacent inner faces of the outer legs 16 of the core, the side extensions 18 and the air gaps 20 providing shunt paths for leakage flux. In order that the transformers may have high reactance, the reluctance of these shunt paths must be low and for very high reactance it is desirable that the air gaps 20 be very thin to avoid the necessity of unduly large crosssection in the extensions 18. In some cases, air gaps four-thousandths of an inch thick have been found desirable. The notches in the inner faces of the yokes 15.hold the winding leg 17 and its side extensions 18 very rigidly'and accurately in position and this is of advantage in assuring accuracy in the thickness of the air gaps 20.

\Vhat I claim as new and desire to secure by Letters Patent of the United States, is:

1. A transformer including a magnetic core having a winding leg and two outer legs, yokes connecting said legs, the ends of said winding leg being disposed in notches in the inner faces of said yokes, a primary winding surrounding one end and a secondary winding surrounding the other end of said winding leg, and magnetic members integral with said winding leg and disposed between said windings, there being nonmagnetic gaps between the outer ends of said members and said outer core legs.

2. A transformer including a magnetic core having a winding leg and two outer legs yokes connecting said logs, the ends of said winding leg being disposed in notches in the inner faces of said yokes, a primary winding surrounding one end and a secondary winding surrounding the other end of said winding leg. and a magnetic member between each of said outer core legs and said winding leg and disposed between said windings. each of said magnetic members being formed integrally with the leg adjacent one end thereof and havin a non magnetic gap between its other cut and the leg adjacent thereto.

In witness whereof, I have hereunto set my hand this 8th day of Sept, 1925.

RALPH H. CHADWICK. 

